from os_ken.base import app_manager
from os_ken.controller.handler import set_ev_cls
from os_ken.services.protocols.bgp import application as bgp_application

from os_ken.controller import ofp_event
from os_ken.controller.handler import CONFIG_DISPATCHER, MAIN_DISPATCHER
from os_ken.controller.handler import set_ev_cls
from os_ken.ofproto import ofproto_v1_3
from os_ken.lib.packet import packet
from os_ken.lib.packet import ethernet
from os_ken.lib.packet import ether_types


class MyBGPApp(app_manager.OSKenApp):
    _CONTEXTS = {
        "os_kenbgpspeaker": bgp_application.OSKenBGPSpeaker,
    }
    OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]

    def __init__(self, *args, **kwargs):
        super(MyBGPApp, self).__init__(*args, **kwargs)

        # Stores "os_ken.services.protocols.bgp.application.OSKenBGPSpeaker"
        # instance in order to call the APIs of
        # "os_ken.services.protocols.bgp.bgpspeaker.BGPSpeaker" via
        # "self.app.speaker".
        # Please note at this time, "BGPSpeaker" is NOT instantiated yet.
        self.app = kwargs["os_kenbgpspeaker"]
        self.mac_to_port = {}

    @set_ev_cls(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER)
    def switch_features_handler(self, ev):
        datapath = ev.msg.datapath
        ofproto = datapath.ofproto
        parser = datapath.ofproto_parser

        # install table-miss flow entry
        #
        # We specify NO BUFFER to max_len of the output action due to
        # OVS bug. At this moment, if we specify a lesser number, e.g.,
        # 128, OVS will send Packet-In with invalid buffer_id and
        # truncated packet data. In that case, we cannot output packets
        # correctly.  The bug has been fixed in OVS v2.1.0.
        match = parser.OFPMatch()
        actions = [
            parser.OFPActionOutput(ofproto.OFPP_CONTROLLER, ofproto.OFPCML_NO_BUFFER)
        ]
        self.add_flow(datapath, 0, match, actions)

    def add_flow(self, datapath, priority, match, actions, buffer_id=None):
        ofproto = datapath.ofproto
        parser = datapath.ofproto_parser

        inst = [parser.OFPInstructionActions(ofproto.OFPIT_APPLY_ACTIONS, actions)]
        if buffer_id:
            mod = parser.OFPFlowMod(
                datapath=datapath,
                buffer_id=buffer_id,
                priority=priority,
                match=match,
                instructions=inst,
            )
        else:
            mod = parser.OFPFlowMod(
                datapath=datapath, priority=priority, match=match, instructions=inst
            )
        datapath.send_msg(mod)

    @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
    def _packet_in_handler(self, ev):
        # If you hit this you might want to increase
        # the "miss_send_length" of your switch
        if ev.msg.msg_len < ev.msg.total_len:
            self.logger.debug(
                "packet truncated: only %s of %s bytes",
                ev.msg.msg_len,
                ev.msg.total_len,
            )
        msg = ev.msg
        datapath = msg.datapath
        ofproto = datapath.ofproto
        parser = datapath.ofproto_parser
        in_port = msg.match["in_port"]

        pkt = packet.Packet(msg.data)
        eth = pkt.get_protocols(ethernet.ethernet)[0]

        if eth.ethertype == ether_types.ETH_TYPE_LLDP:
            # ignore lldp packet
            return
        dst = eth.dst
        src = eth.src

        dpid = format(datapath.id, "d").zfill(16)
        self.mac_to_port.setdefault(dpid, {})

        self.logger.info("packet in %s %s %s %s", dpid, src, dst, in_port)

        # learn a mac address to avoid FLOOD next time.
        self.mac_to_port[dpid][src] = in_port

        if dst in self.mac_to_port[dpid]:
            out_port = self.mac_to_port[dpid][dst]
        else:
            out_port = ofproto.OFPP_FLOOD

        actions = [parser.OFPActionOutput(out_port)]

        # install a flow to avoid packet_in next time
        if out_port != ofproto.OFPP_FLOOD:
            match = parser.OFPMatch(in_port=in_port, eth_dst=dst, eth_src=src)
            # verify if we have a valid buffer_id, if yes avoid to send both
            # flow_mod & packet_out
            if msg.buffer_id != ofproto.OFP_NO_BUFFER:
                self.add_flow(datapath, 1, match, actions, msg.buffer_id)
                return
            else:
                self.add_flow(datapath, 1, match, actions)
        data = None
        if msg.buffer_id == ofproto.OFP_NO_BUFFER:
            data = msg.data

        out = parser.OFPPacketOut(
            datapath=datapath,
            buffer_id=msg.buffer_id,
            in_port=in_port,
            actions=actions,
            data=data,
        )
        datapath.send_msg(out)

    @set_ev_cls(bgp_application.EventBestPathChanged)
    def _best_patch_changed_handler(self, ev):
        self.logger.info(
            "_best_patch_changed_handler: %s/%s", ev.path.nlri.addr, ev.path.nlri.length
        )
        self.logger.info("_best_patch_changed_handler: %s", ev.path.source)
        
        pass

    @set_ev_cls(bgp_application.EventAdjRibInChanged)
    def _adj_rib_in_changed_handler(self, ev):
        self.logger.info(
            "_adj_rib_in_changed_handler: %s/%s", ev.path.nlri.addr, ev.path.nlri.length
        )
        self.logger.info("_adj_rib_in_changed_handler: %s", ev.path.source)
        pass

    @set_ev_cls(bgp_application.EventPeerDown)
    def _peer_down_handler(self, ev):
        self.logger.info("_peer_down_handler: Peer down: %s", ev)
        pass

    @set_ev_cls(bgp_application.EventPeerUp)
    def _peer_up_handler(self, ev):
        self.logger.info("_peer_up_handler: Peer up: %s", ev)
        pass
